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MG MGA - Rear axle seal

Have just pulled the rear axle shaft to find oil saturated brake shoes. My car has the modified o-ring seal and the very thin paper washer.
Are they all that holds the oil in?
I think the o-ring has compressed over the years, so will replace that, but, is there anything else I can do?
Barry
BM Gannon

Bm,
When I installed the o-ring I found the replacement was a bit too big in circumference for the groove it was to be placed in.
I would be very watchful, when setting it in the groove as it tends to jump out of place as soon as you turn your head. Maybe some very sticky grease would help.

Ray
Ray Ammeter

It all depends on where the oil is leaking from. The seal in back of the hub could be bad. To replace that seal you would need one of the special octagonal sockets.

Jeff Schultz

I second Jeff's suggestion. When - after 44 years - my MkII started leaking oil into the right rear brakes, I decided to check the hub seal. Upon straightening out the tab washer I found that the large octagonal nut could be turned by hand. Imagine my surprise having been prepared to muster all my strength to remove it! The leak was evidently caused by the wobble permitted by the loose nut. I suspect the loosening of the nut was caused by vibrations resulting from a bad rear shock, which had come evident - and I had replaced - a short time before the seal started leaking.
Steve K

Barry
When I replaced mine I used a little RTV on both sides of the paper gasket to help seal it and as suggested a little axle grease to hold the O ring in place.
Kris
Kris Sorensen

Funny, I just completed the same repair this week. I replaced both the O ring seal and the seal in the back of the hub. You can buy quality seals from Moss. I used a pipe wrench to remove the octagon nut with no problem at all. The octagon socket cost about $55 so try the pipe wrench first. You will need a puller or a slide hammer to remove the hub and you will also need to remove the bearing.

The job was easier than I expected. Good luck!
Jeff Bennett

Whatever wrench you use make sure it fits well. Getting the nut off is just half the problem. When replacing the nut it needs to be tightened to at least 140 ft-lbs to avoid the problem that Steve talked about. There is a socket for a Ford 4x4 that is cheap and works good, but it might be hard to find in Australia.
Jeff Schultz

Thanks for all that advice. I have a socket to fit the large nut and the nuts are in perfect shape. Most of the cars I have worked on have had that nut removed and tightened with a chisel and hammer! I will look at the hub seal, and replace if necessary, while I'm in there.
I will have to borrow a puller. With a bit of luck there might be one in the local club.
Thanks again, Barry
BM Gannon

I've included an old post from the archives below where I recorded my steps for rear oil seal replacement.

An important point is the size of the O-ring for your particular hub. There are two sizes, and I believe Moss had some issues with getting the right sizes in the past.

If it pops out or bulges you may have the wrong size O-Ring for your hub.

Anyone had any recent experience with sourcing these O-Rings and getting it right ?

-Chuck

Posted 30 September 2005 at 14:57:50 UK time
Chuck Mosher, Texas, USA

I just finished up this R&R on my 1600 MKII.
Here's my recipe:

Tools:
#3 Phillips screwdriver
Cold chisel
Wood chisel (You won't use it on wood again)
1 61/64" octagonal socket (Moss 384-905)
Long handle socket bar
Brass drift punch

Parts:
Oil Seal (Moss 120-900)
O-ring (Moss 121-400)
Paper gasket (Moss 296-100)
Octagonal nut lock tab (Moss 267-450)
Hub lock tabs (2 x 267-450)

Replace octagonanl nut (267-440 or 430) if someone took a cold chisel or pipe wrench to it earlier.

Remove the wheel, then use wood chisel to separate the lock tabs on the 4 hub nuts enough to where you can use the cold chisel flatten them out. Remove the 4 nuts and lock tabs.

Be sure you have the brakes backed off - especially the parking brake. Also back off the adjuster on the rear slave cylinder through hole in the hub. The hub should pull right off. Be carefull not to nick the threads on the 4 hub nuts.

Use the #3 Phillips to remove the set screw that holds the hub to the bearing housing. The axel should now pull right out, unless someone used gasket sealer on the old paper gasket. Try the wood chisel again to loosen if needed.

Use the wood chisel once again to separate the lock tab on the octagonal nut, followed but the cold chisel to flatten. Be careful here, you're right next to the bearing now.

You really need the octagonal socket at this point. It isn't the best quality tool, being pressed rather than forged, but it worked for me. Take care to keep it centered on the nut, and back off if it starts to slip. If you're on the left hand side, remember that that that side has left hand threads.

Use your rawhide hammer to loosen the bearing assembly, and it should pop right off. Lay it down on your workbench on a couple of 2x4's, supported by the 4 hub bolts. Use the brass drift and a small hammer to tap on the outer race and slowly work it out of the hub. Remove the old seal the same way.

See mgaguru.com if you can feel ridges on the axel where the oil seal turns, you'll need the "speedi-sleeve". If not, replace the oil seal and return the bearing and hub assembly onto the axel. Be sure and use a new lock tab, not the old one, torque down the octagonal nut (140 ft-lbs !?) and use the chisels to set the lock tab.

Last trick is to be sure and put the o-ring on the half-axel, not in the groove on the hub/bearing unit. It is easy for it to get out of place and get pinched or nicked when you slide the axel back in. Don't forget the paper gasket.

That about does it! Worked for me, but I'm sure that there are plenty of other things that could go wrong.

Only took me a couple of hours to get this done. Second one done in 30 minutes, once I had the tricks figured out.

Best regards,
Chuck Mosher


Chuck Mosher

Chuck, Thanks for that. I have already got the correct o-rings and now will tackle the hubs and fit new oil seals.
Barry
BM Gannon

This thread was discussed between 01/03/2008 and 05/03/2008

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This thread is from the archive. The Live MG MGA BBS is active now.